Re: HowTo: Undervolt your notebook CPU for longer battery life

Will undervolting affect the performance of the laptopz/ It seems to me that if it is using less power, it will be less powerful.

Also, I was wondering if my battery might not be fully enabled. I have an extra battery pack and in Vista I was able to get 10 hours, with Ubuntu, I get about 4.5 hours and I am assuming that Vista uses more power than Ubuntu.

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Re: HowTo: Undervolt your notebook CPU for longer battery life

Will undervolting affect the performance of the laptopz/ It seems to me that if it is using less power, it will be less powerful.

Performance will be the same. The power you saved was just wasted before, did nothing good.

Originally Posted by M4rotku

Also, I was wondering if my battery might not be fully enabled. I have an extra battery pack and in Vista I was able to get 10 hours, with Ubuntu, I get about 4.5 hours and I am assuming that Vista uses more power than Ubuntu.

Is the second battery shown, i.e. in the tray icon or in /proc/acpi/battery?

Win might be a little better in powersaving, but still the difference you post is huge!

Originally Posted by w4ngsta07

Is it possible for you to also make a HOW-TO for compiling the linux phc in case our kernels get updated?

It is not that simple to do and I can't really make a generic how-to for that as I don't know if extra workarounds will be needed. Second, for the new kernel there might be the need of a new patch form the PHC guys.
In the link I gave right at the top there is a german how-to for .16.

In case of a kernel change just try your old .17 module again. If that doesn't work give me a PM and I'll look into it and make a new module.

Re: HowTo: Undervolt your notebook CPU for longer battery life

Is the VID read from the script or from the chip? I have a T8300 in my T61, and the script bugged out on me, because even when both cores were fully loaded, the script reached 0 on the highest clock level without a crash.

Also, there are two problems (typos) with the guide. One is when you point to the original acpi-cpufreq.ko, you have two kernel/ directories. The second one is when you talk about loading the second core; the command burnmmx does nothing, but burnMMX works. Other than that, extremely helpful

Re: HowTo: Undervolt your notebook CPU for longer battery life

Can you provide some hard numbers on what the power savings is like before and after on your machine. Something like cleanly booting the machine, logging in, unplugging the AC power, waiting for a few minutes and then running powertop like this (don't touch the machine for 5 minutes after this):

Code:

sudo powertop -d -t 300

Having the average watts used during a 5 minute powertop run on an idle system would be an interesting baseline. I'm interested in trying this out but only if there is a noticeable drop in power usage.

Don't try to make something "fast" until you are able to quantify "slow".